UNI-T UTG1000A User Manual page 25

UTG1000A Series Function Generator User Manual
 Square wave: duty cycle is 50%
 Rising Ramp Wave: symmetry degree is 100%
 Falling Ramp Wave: symmetry degree is 0%
 Arbitrary Wave: when arbitrary wave is modulated waveform, DDS function generator
limits arbitrary wave length as 1kpts in the way of random selection
 Noise: White Gauss noise
2) External Source
When modulation source is external, parameter list will hide the modulation wave option and
modulation frequency option, and carrier waveform will be modulated by an external waveform. AM
modulation depth is controlled by ±5V signal level of external modulation input terminal. For example,
if modulation depth value is set to 100%, AM output amplitude is the maximum when external
modulation signal is +5V, AM output amplitude is the minimum when external modulation signal is -5V.
Modulation Shape Frequency Setting
When modulation source is internal, frequency of modulation shape can be modulated. After enabling
AM function, range of modulation wave frequency is 2mHz~50kHz (default is 100Hz). Press
Parameter→Modulation Frequency to change. When modulation source is external, parameter list will
hide the modulation shape option and modulation frequency option, and carrier waveform will be
modulated by an external waveform. The range of modulation signal input from external is 0Hz~ 20Hz.
Modulation Depth Setting
Modulation depth indicates the extent of amplitude variation and is expressed as percentage. Suitable
setting range of AM modulation depth is 0% to 120%, and the default is 100%. When modulation depth
is set to 0%, the constant amplitude (a half of the carrier wave amplitude that has been set) is output.
Output amplitude changes as modulation waveform changes when modulation depth is set to 100%.
The instrument output a peak-peak voltage less than ±5V (is connected with 50Ω terminal) when
modulation depth is more than 100%. If need to change, press Parameter→Modulation Depth in
amplitude function interface. When modulation source is external, output amplitude of the instrument
is controlled by ±5V signal level of external modulation input terminal (Input/CNT probe) in rear panel.
For example, if modulation depth value in parameter list has been set to 100%, AM output amplitude is
the maximum when external modulation signal is +5V, AM output amplitude is the minimum when
external modulation signal is -5V.
Comprehensive Example
Firstly, make the instrument work in amplitude modulation (AM) mode, then set a sine wave with
200Hz from the internal of the instrument as a modulation signal and a square wave with frequency of
10kHz, amplitude of 200mVpp and duty cycle of 45% as a carrier wave signal. Finally, set modulation
depth to 80%. Specific steps are seen as following:
1) Enable Amplitude Modulation (AM) Function
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